Automatic motor-starter.



PA'JEINTIEID MAY 2 6, 1908.

E. H. SMY'I'H'E. AUTOMATIC MOTOR STARTER.

APPLIU'TI'ONTILBD AUG. 17. 1905.

`4 SHEETS-Burr 1.

'A No. 888,759.

l PATENTED MAY 26. 1908.v H.SMYT HE; AAUTOMATIC MOTOR'STARTBR,

Arrmouxon FILED 11118.17-, 1805.

' 4. SHEETS-sum* 2.

No. 888,759. y TATENTED MAY'ze, 1908.

E. H. SMYTHE.

4 SHEETS-SHEET 3.

PATENTED MAY 28, 1908.

"8., H. SMYTHE.

AUTOMATIC MOTOR STARTER.

APPLICATION FILED 888.17, 1985s.

4 sinn'rs-snwn.

UNITED STATES APATE/INIT OEEIOE'.

EDWIN IIsMYTEE, OE CHioA-co, ILLINOIS, Assis-NOE To wEsTEEN ELECTRIC COMPANY,

or CHICAGO, ILLINOIS, A CORPORATION OE ILLINOIS.

AUTOMATIC MOTOR-STARTER.

Nolsssnta f Sbecication of `Letters Patient.

. ,rasantes my '26, 190s.

Application" mea August 17,1905. 1 sensing. 274,616.

To .all 'whom itmy concern.: I

Be `it`known that I, EDWIN H. SMYTHE,

useful" Improvement in Automatic Motor- S4tarters, of V,which Athe following is' a full,-

clear, concise, and exact `.de scription .,v

`My invention relates to a device for gradually and safelyl regulating the flow OfcurrenttlIrOugh/a motor when it is being started vin motion, and comprises an electromagifet automatically Operated according vto the.

I .varying potentials lof the Inotor armature to' successively cut out portions of a resistance Included '1n thelarmature circult.,

' full strength'of the current' is suddenlyahv lowed to flow through the motor armature, the parts vare 'likely to be injured, especially if 4the motor be under a heavy'load. Hence .various meanshave been devised for lrstI admittinlg'al Weak current^to the motor and 'gradually increasing the Current i flowing therethrough until Itheifull current strength.

for whiehlthe motor is adapted is reached.

` It has been customary to include resistances jin the.l armature circuit of the motor throu-Uh which the current iii-st Hows when the switch is closed and to gradually cut Ou-t the resistances after the motor has st rted.y Onev means hitherto devised for cutti g out these resistances comprises a brush sliding over 'a series of contacts connected toftheresistance so--that increased portionsI of saidv resistance are short-circuitedas the brush moves over the contacts. Another vwell lmown means comprises a series Of electromagnets 'which are arranged to be successively operated as the counter electromotive force of the motor increases, and so connected as to' controlthe resistance in the-rnotorcircuit. While this latter means overcomes the sparking 'and scribed means, and furthermore regulates the admission of'current inproportionito the load, it is itself open to objections. Anumber of electromagnets are required, one for each resistance tosbe cut out. Moreover,',as

the resistances are out out by a short' circuit.

through the Icontacts of the armatures with their electromagnets, thep'ositiveness of the contact dependsfon the strength of the current flowing through the electromagnet. This in turn varies as the speed yof the motor increases;v Hnce when the .circuit cutting 'out a resistance 4Is closed -a strong Contact -does nbt at/flrst result.

In my invention a series oflbridging membridging 'positionone after' the"'other as the late the Inovevarmatureof,the motor speeds up. Asolenoid, 'energized 'when vthe switch connecting the'motortothe mains is closedin the 'act O starting-up-the motor, operates toplaoethe jentire seriesof brid ing members 1n condition to, have their c Osure regulated by the. Asis well `known, if in starting a motor .the

cams, the `movements of which4 are Controlledby' a'-second' solenoid, arranged to operate on the difference of potential lcaused .by the speeding up of the motor, the coreof the solenoid being graduali moved to rotate 'the cams and thus contro thel operationl of the brushes in cutting out theresistanelir The' `positive/nessy ofv the 'armature circuit. the contact of the b'rushis dependent upon a. spring or other mechanica'means; and hence a'good contact results. 'It'wil-l be seen, therefore, that after the bridging members are `brou ht bythe action'of a solenoid,v or `other suita le means, into Operative condition, a'v single electromagnet serves to regulate the operation oflsaid bridging members to graduallyA ct out' the resistance in the motor armature, 'and that .a positive, direct and uniform contact-is produced when a resistance is cut out. Moreover, by m invention, the rapidity with-which the fu lcurrent strength is turned en the motor is `automatically dependent. uponthe-load.

I will describe my invention morelparticul'arly by reference to the accompany-ing drawings, in which Figure 1 is a diagram showing the Acourse of the main and shunt currents through the motor and the starting device; Fig.v 2 is' ai front elevation of the starting device lfig. 3 is a-,sideelevation thereof ,Fig 4 is a sectional view on the line 4--4 of'Fig. 2v, showing the osition of the arts prior to the closing of t Ie switch Whidli connects the motor to the. mains; and Fig. 5 a .corresponding View,` showi the po'sltiorrfof the parts after the motor swltch .is closed `and after the. de-

vice .has operated to cut outv part'of. the

resistance.

:secured to the framewor The saine letters of reference are used to designate the saine parts wherever they are shown As illustrated in Fig. l when the switch is closed to coimect the motor with the mains,

the current from the terminals will be closed through the `conductor 1, the shunt field magnet coils A, and conductor The main circuit is also closed through the conductor l, motor armature M, resistance R and conductor '2. A shunt circuit leads from conductor 1 through conductor la, which in` cludes the windings of the solenoid S to conductor 2.

A shunt circuit also leads from con ductorl. through the conductor 1b, which includes the high resistance windingsof the solenoid S'. -v i vItis apparent that immediately upon the l switch'being closed to start the motor, a comparatively weak current passes'y through themotor, owing to the resistance R through which it must flew: At the lsame time curq rent `flowing through the solenoid S causes it 'to draw .in its core or plunger a.

Said core at its upper end has a slotted pivoted 'connection with one end of an arm c, the other end of which is keyed. to a shaft i), having suitable bearings" in a stationary bracket secured to the framework. fHence whenl the magnet S is excited and moves its core a, the

yshaftv b is partially rotated. Upon the'shatt b are loosely mounted a series of bit'urcated levers t', each carrying at` '2 and the tov les not beiner in o )erative re J b b however,f partially counterbalancesy lation with the cams d. w In this position the pin o is in ,contact with the key p on the lever a, and holds the roller t" in the recess g in the arm g. However, upon the closing of the motor switch, the. core c of thesolenoid S is drawn inward against the force of the coiled spring s. This produces a partial rotation of the shaft b, in the manner herein before described, the pin o is moved from engagement with the stop p, anda spring n,

secured to the shaft and bearing against theA link m comes under tension and causes theV roller 'ito tend to ride vupward on the arm g, pressing saidarm downward into operative relation .with the cam d. The spring i2, the downward pressure *on the arm g and prevents too greatta frictional engagement of said arm with the cam. `As shown in thev drawing, there is a series of these springs n,

' one associated with each toggle lever.

1 The camsd are keyed tp a shaft e, having cut out another its bearings in brackets secured to the framework. Keyed to the shaft c is the arm c', and to the other end of said arm is pivotally secured the core c of the solenoid S. When the solenoid S attracts its plunger' or core piece, the shaft e and the cams d keyed thereto are rotated. The cams are so positioned on the shaft that the depressed faces f thereof are successively presented to the arms g as the cams are rotated, and thereby the bridg ing members h are successively operated, in a manner hereinafter more fully described, to` close the circuit and cut out part of the resistance R of the armature circuit.

` The magnet S is so wound that the counter electromotive force developed by the armature of the motor when the armature circuit is closed will operate to energize the solenoid S sufficiently to partially draw in the core-a. against the'pressur'e of thespring s. This causes a partial rotation of the shaft e and its cams d, to bring the depression f ofthe cani beneath the arm g, so that the arin` sinking into the depression permits the tension of the spring a to cause the roller 'L' to ride upon the arm and to operate the arm l" through the link m. The contact points h of the bridge member are thus firmlv seated, so as to short-circuit a portion of the resistance R.

The increased :[iow of current through the 95 motor resulting from the cutting out of a portion of the resistance, increases the counter electromotive force and thereby Vmorestronglyl energizes the electromagnet S',

which draws its core piece a still farther inward,.and thereby further rotates shaft e and brings the .depression of thesecond cam in position beneath the second arm g, where upon the secondbridge member is caused to ortion of the resistance R. As the amount ot current iiowing through the motorincreases as resistance is cut out of the motorr armature, the counter electromotive force likewise increases, and the resistance R will be graduall cut out, in the manner above 110k described7 at. w ich time the motor will have attained its vpro er speed and be capable of receiving the ful amount of the current supplied by the mains.

lt will be observed that the rapidity with which the resistancein the motor'armature is cut out lby my motor starting device is thus automatically determined.v and is inverselv proportional to the load. Viith a light load, the. current lis rapidly turned on; with a heavy load, the current is more slowly ad initted. Thus, injury to the motor from too sudden admission of the current therethrough is pijevented. V

hen the switch is operated to disconnect .the motor from the mains, my starting device `is restored to the position shown in Figs. l `and 4, in the following manner: The solenoid S being no longer energized, Vthe spring S- kforces out the core c, thus mtatingthe' shaft 13o li in a direction reverse to that before described'. rIhe pin o on the shaiitkcontacts with :i stop p of the lever 'i and forcesthe lever downward until the roller i. rests in the groove g in the arm g, in which position the dowirwari'l pressure of the roller 'i' upon the arm g, due to the pin o on shaft l) pressing against stop p on the lever-i, is counterbalanc'ed by theupward pull of thc` spring i2,

and the lparts are out of operative contact with thc camsd. n The core c being likewise forced out bythe spring s of the solenoid S', rocks the shaft e and restores the camsgd to their initial position.

l. "lne combination with an electric motor and its circuit', of a resistance in said circuit,

'a ser` of switch. members each adapted to eut out a portion of the resistance, a magnet adapted to be controlled by varying currents, and cam mechanism actu ated by said magnet to regulate the successive operation of said switch members.

2. The 'coinliinatio'nwith an electric motor and-its circuit, ofa resistance in the motor circuit, a series of switch members each ad aptcd to cut out a portion oi the resistance, moans tendinar to close said' switch ii'iembers,l

.means normally .obstructing` the closure A under tension tending to close the saine,

means normally obstructingT the closure of said switches, and an electromagnet energized according to the varying potential of the motor armature for reiii'ovi-ng;r in succession said switch obstructing means.

4. ln a motorstartingI device, the combination: with the motor, ofv a-resistance in't eluded in the circuit thereof, 'a lsolenoid auto-- matically energized according to the :varying potential of the motor-armature, a movable core for said solenoid, a shaft having?T a seriesY o'fcamsmounted. thereon, a connection between saidcore and 'shaft whereby the Inove-` mcnt -of' the core' rotates the cams, and ,al series of toggles autom atically operated upon the 'rotation of. said 'cams to successive]y." short circuit i'io'rtions ot said resistance. 5'

5. The combination with an electric motor' and its` circuit, oi a resistance in, the motor circuit, a series ot toggle s'witcl'i i'ncmbers each adapted to cut out a portion of the resistance, an cleetromagnct, moans operated by said magnet for putting' tl ,1 'itch members under-tension tending to close the same,

an electromagnet' energized iicifordiirgr to the varying potential ofthe motor armature, and

tion of said second-named magnet for regulating the successive closingr of said switch members. v

6. The combination with. an electric motor and its circuit, of av resistance inthe motor circuit, a series of switch members each adapted to cut out a' portion of the resistance, a solenoid adapted to bev controlled by the inni-'ement of said core, saidcam mechanism being:A arranged tocontrol thcrsucces'- sive o .eration of said switch members.

7. a; motor starting device, the combination 'with the motor, lof a resistance iiieluded in the circuit of the motor, a solenoid.

of cams secured thereto, a'connection between the core and the shaft whereby the movementof the core -rotates the cams, and

' upon the rotation of said series of cams to suc cessi vely cut out portions of saidjresistance.'

The combination with an electric moto. and its circuit, of .a resistance in the motor circuit, a series of toggle switch members Yeach adapted to cut. out aportion ci' the-rfcsis'tance', .al solenoid having,r a movable core for putting; the switch members under tension tendingto close the same, 'a second so. lenoid having a core the lmovement ofwhich is automatically regulated according to vary# ing currents,`,an'd .means actuated by the e movement of said second named core for controllingthe successive operation o'f Vsaid series of switch members.

nation with the. motor, of a 'resistance 1ncluded. in" the circuit thereof, a series of switch ,members each adapted l to cut' out a 'portionof said resistance, means for initially putting said members under tension tending to close the same, a series of cams arranged to successively control the operation of Sa'id members, a solenoid having a'coic the movement of which is automatically regulated according to varying currents, and a connection between said core and cams; where- -by the movement of the core rotates the cams and thereby permits the .successive automatic operation ofthe switch members to cutout the resistance, v

, 0. The c ombinationwith tor and its circuit, of a resistance in the motor cfifrcuit, a series of switch members each lada ted to cut out a portion of the resista-nce, 'a :haft upon which" said members are mounted, a solenoid having a core the move.A ment of which is adaptedto rock Saidshaft and put said switchimer'nbers under tension teilt-ling to close the same, a series olcaims with a movable core automatically controlled by varying currents, 'a shaft having a series a series of toggles automatically operated- 9. lInra motor starting device, thevcombi` an electric mocain mechanism controlled bythe energica-- varying;- currents, a movable'core for said', solenoid, and cam inechimisni controlled by normally preventing (he closure of said switch members, a shaft' u )on which s-Lid `cams are mounted, and a so enoid having a core the movement ol' which is automatically regulated according to varying currents, and

which is adapted to rotate said shaft to rotate said cams; whereby the switch memn bers are successively' actuated to out' out said resistance as the speed of the motor armature increases 11; ln a motor starting device, the combination wit-li the motor, of a resistance includcd in the circuit thereof, a shunt circuit including a solenoid, a plunger moved by the solenoid, a. rock-'shaft carrying a series 'of toggle levers having contact bridging niembers thereon, a connection between the shaft and the plunger whereby the movement of the latter rocks the shaftland puts said togglcs under tension, a second solenoid adaptedj to be energlzed according to varyingl cur rents, a plunger moved by said second solen 4oid in proportion to the energization thereof, a shaft carrying a series ofcanis thereon corres )onding to said series of t'ogg'les and norma ly preventing the operation of the same, said cams being arranged to control theV successive operation of the toggles, and i a connection between said seeondnamed shalt'and plunger, whereby the movement of the`v lunger rotates the cams and automatical y regulates the successive cutting out .of portions of said resistance;

12. In a motor starting device, the combi 4shaft to rotate said cams;

nation with the inotor, of a resistance included in thc circuit thereof, a shunt circuit including a solenoid, a rock-shaft having a series of pins and springs thereon, a series of togglc levers looselyinountcd on said shaft, .bridging members carried by said toggle levers, a connection between the shaft and the fplun'ger, whereby the outward move mentv of the plunger causes an engagement of said pins with said levers and places the latter in an inoperative position, and whereby the movement of the plunger in the re verse direction releases the pins and'places the springs under tension which tends to operate said bridglng members, a series of' cams normally preventing the. actuation of `said bridging members, said cams being arranged to' control the successive actuation of the bridging members, a shaft upon which said cams are mounted,- a second solenoid --having a core the movement of which is automatically regulatedaccording to varying currents land which is adapted to rock said whereby the switch embers are successively and automatical y actuated to'cut out said resistance as the-speed of the' motor armature increases. Inwltness whereof, l hereunto subscribe my name this 31st day of July, A. D., 1905.

EDWIN H. SMYTHE.

Witnesses t' 'ELLA Einem,-

IRVING MACDONALD. 

